1. Field of the Invention
The invention relates to an interface needle, and more particularly, the invention relates to an interface needle for connecting a syringe to a catheter to create a blunt interface between liquids being delivered through the catheter.
2. Brief Description of the Related Art
The delivery of fluid compositions which solidify in vivo is particularly useful for a variety of reasons including treatment of blood vessels, tumors, aneurysms, arteriovenous malformations (xe2x80x9cAVMsxe2x80x9d), arteriovenous fistula (xe2x80x9cAVFxe2x80x9d), uncontrolled bleeding and the like, as well as in the sterilization of mammals by blocking the vas deferens or fallopian tubes, in the treatment of urinary incontinence by the addition of a bulking agent to the periurethral tissue, and the like.
Delivery of such compositions is preferably accomplished via catheter techniques which permit the selective placement of the catheter at the delivery site. For example, recent advancements in catheter technology as well as in angiography now permit neuro endovascular intervention including the treatment of otherwise inoperable lesions. Specifically, development of microcatheters and guidewires capable of providing access to vessels as small as 1 millimeter in diameter allows for the endovascular treatment of many lesions.
Fluid compositions which are delivered for in vivo solid mass formation generally include a solvent such as ethanol, acetone, ethyl lactate, dimethylsulfoxide (xe2x80x9cDMSOxe2x80x9d), or aqueous solutions of ethanol or DMSO, a biocompatible water insoluble polymer, and a water insoluble contrast agent. Preferably, however, the solvent is non-aqueous in order to maximize the amount of biocompatible water insoluble polymer which can be dissolved therein. Once delivered, the solvent dissipates from the polymer forming a solid polymer mass.
In practice, the catheter tip is directed to the vascular or other delivery site by use of conventional visualization techniques such as fluoroscopy, and the like which allow the clinician to visualize and direct the catheter tip. After placement of the catheter, the composition is introduced into the catheter with a syringe and delivered to the delivery site by the catheter. Upon delivery, the solvent dissipates into the blood, fluid, or tissue and the water insoluble polymer precipitates to form a coherent mass which solidifies in vivo.
One use of this liquid embolic polymer composition is in minimally invasive procedures for treating intracranial aneurysms. The use of liquid embolic compositions addresses the problems with the known aneurysm treatment methods, such as surgical clipping and coil delivery, and involves the endovascular injection of the liquid embolic composition which solidifies in the aneurysm to occlude the aneurysm. Typically, the liquid embolic composition will include a water insoluble, biocompatible, non-biodegradable polymer dissolved in a biocompatible solvent. Once the liquid embolic composition is injected into the aneurysm, the biocompatible solvent dissipates into the blood and the polymer solidifies to occlude the blood flow into the aneurysm. These liquid embolic compositions preferably include a radiopaque material or contrast agent which allows the physician to view the embolization procedure by fluoroscopy or other visualization techniques.
The liquid embolic composition is delivered to the catheter with a syringe connected to the catheter hub. Often the liquid embolic composition is delivered after an aqueous solution such as an aqueous solution containing a contrast agent which is used to visualize blood flow at the aneurysm site. After delivery of an aqueous contrast solution or other aqueous solution the catheter is then flushed with the biocompatible solvent. Flushing with the biocompatible solvent will prevent the catheter line from become plugged due to premature precipitation of the biocompatible polymer in the presence of the aqueous solution. However, when delivery of the biocompatible solvent is followed by delivery of the liquid embolic composition this results in some mixing of the liquid embolic composition and the biocompatible solvent at a liquid interface. The mixing results in a diluted polymer composition having a low viscosity which is difficult to deliver and tends to form strands upon delivery. Strands of the polymer composition may be carried away in the blood stream where the polymer can occlude an undesired vascular location. In addition, the mixed liquid at the liquid interface makes it difficult to detect the first appearance of the polymer composition in vivo.
Accordingly, it would be desirable to provide a delivery system for reducing mixing of two sequentially delivered liquids, such as a biocompatible solvent and a liquid embolic composition.
In addition, it is difficult to deliver liquid embolic compositions of a biocompatible polymer, a biocompatible solvent, and a biocompatible contrast agent including greater than eight weight percent polymer, based on the entire weight of compositions through conventional neuro catheter delivery systems because these high viscosity compositions require high pressures for injection that may rupture the catheter system. However, in some instances it is desirable to deliver higher viscosity embolic compositions, for example compositions containing more than eight weight percent of a polymer. These higher viscosity embolic compositions are generally easier to position within an aneurysm. The higher viscosity may also help to prevent portions of the polymer from being separated from the polymer mass and being carried away in the blood stream where the polymer can occlude an undesired vascular location.
Accordingly, it would be desirable to provide a delivery system for delivery of high viscosity liquids through small lumens while preventing rupture of the delivery system.
The present invention relates to a device, system, and method for establishing a blunt interface between two delivered liquids.
The invention also relates to a device, system, and method for delivering high viscosity fluid through a vascular delivery system.
According to one aspect of the present invention, a device for creating a blunt interface between delivered liquids includes a body having a proximal end configured for connection to a syringe and a distal end opposite the proximal end configured to be attached to a cannula hub. A tapered lumen extends through the body from the proximal end to the distal end and the lumen has a first diameter at the proximal end and a second smaller diameter at the distal end. A tube extends from the distal end of the body and delivers liquid directly to a lumen of the cannula bypassing a reservoir in the cannula hub.
According to another aspect of the present invention, a system for creating a blunt interface between delivered liquids includes a syringe; a cannula having a cannula lumen, a cannula hub with a female luer fitting, and a reservoir within the cannula hub; and a bypass device connectable to the syringe and the cannula hub. The bypass device has a tube for delivering liquid directly to the lumen of the cannula bypassing the reservoir in the cannula hub.
In accordance with a further aspect of the present invention, a method of delivering two liquids includes the steps of delivering a first liquid through a cannula with a first syringe, removing the first syringe from the cannula, attaching a second syringe to a bypass device for creating a blunt liquid interface, connecting the bypass device to the cannula, and delivering a second liquid with the second syringe to create a blunt liquid interface between the first and second liquids.
The present invention provides advantages of reducing mixing and providing a blunt interface between two delivered liquids.